Describe red to a blind person that doesn't understand physics.
You can't. You could give the definition that it is electromagnetic radiation from some wavelength to some other wavelength, but that's hardly a satisfying definition to people who don't know much about physics. It also doesn't allow them to visualise red.
You could describe the emotions it evokes, but the emotional/cultural aspect of red is only one component. There is still a visual component.
You could describe...